PixelPaint: Relate cursor to brush tool size

This patch changes the cursor for the brush tool to a circle of dynamic
size to indicate the region where the tool will apply color changes.

Userland/Applications/PixelPaint/MainWidget.cpp

@@ -17,6 +17,7 @@
 #include "ResizeImageDialog.h"
 #include <Applications/PixelPaint/PixelPaintWindowGML.h>
 #include <LibConfig/Client.h>
+#include <LibCore/Debounce.h>
 #include <LibCore/File.h>
 #include <LibCore/MimeData.h>
 #include <LibFileSystemAccessClient/Client.h>
@@ -1100,9 +1101,11 @@ ImageEditor& MainWidget::create_new_editor(NonnullRefPtr<Image> image)
         m_show_rulers_action->set_checked(show_rulers);
     };
 
-    image_editor.on_scale_change = [this](float scale) {
+    image_editor.on_scale_change = Core::debounce([this](float scale) {
         m_zoom_combobox->set_text(String::formatted("{}%", roundf(scale * 100)));
-    };
+        current_image_editor()->update_tool_cursor();
+    },
+        100);
 
     if (image->layer_count())
         image_editor.set_active_layer(&image->layer(0));

Userland/Applications/PixelPaint/Tools/BrushTool.cpp

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2020, Ben Jilks <benjyjilks@gmail.com>
  * Copyright (c) 2021, Mustafa Quraish <mustafa@serenityos.org>
+ * Copyright (c) 2022, Torsten Engelmann <engelTorsten@gmx.de>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -13,11 +14,20 @@
 #include <LibGUI/Label.h>
 #include <LibGUI/Painter.h>
 #include <LibGUI/ValueSlider.h>
+#include <LibGfx/AntiAliasingPainter.h>
 #include <LibGfx/Color.h>
 #include <LibGfx/Rect.h>
 
 namespace PixelPaint {
 
+void BrushTool::set_size(int size)
+{
+    if (size == m_size)
+        return;
+    m_size = size;
+    refresh_editor_cursor();
+}
+
 void BrushTool::on_mousedown(Layer* layer, MouseEvent& event)
 {
     if (!layer)
@@ -145,9 +155,12 @@ GUI::Widget* BrushTool::get_properties_widget()
         auto& size_slider = size_container.add<GUI::ValueSlider>(Orientation::Horizontal, "px");
         size_slider.set_range(1, 100);
         size_slider.set_value(m_size);
+        size_slider.set_override_cursor(cursor());
 
         size_slider.on_change = [&](int value) {
             set_size(value);
+            // Update cursor to provide an instant preview for the selected size.
+            size_slider.set_override_cursor(cursor());
         };
         set_primary_slider(&size_slider);
 
@@ -172,4 +185,30 @@ GUI::Widget* BrushTool::get_properties_widget()
     return m_properties_widget.ptr();
 }
 
+NonnullRefPtr<Gfx::Bitmap> BrushTool::build_cursor()
+{
+    m_scale_last_created_cursor = m_editor ? m_editor->scale() : 1;
+    auto scaled_size = size() * m_scale_last_created_cursor;
+    auto containing_box_size = 2 * scaled_size;
+    NonnullRefPtr<Gfx::Bitmap> new_cursor = Gfx::Bitmap::try_create(Gfx::BitmapFormat::BGRA8888, Gfx::IntSize(containing_box_size, containing_box_size)).release_value_but_fixme_should_propagate_errors();
+
+    Gfx::Painter painter { new_cursor };
+    Gfx::AntiAliasingPainter aa_painter { painter };
+
+    painter.draw_line({ scaled_size - 5, scaled_size }, { scaled_size + 5, scaled_size }, Color::LightGray, 3);
+    painter.draw_line({ scaled_size, scaled_size - 5 }, { scaled_size, scaled_size + 5 }, Color::LightGray, 3);
+    painter.draw_line({ scaled_size - 5, scaled_size }, { scaled_size + 5, scaled_size }, Color::MidGray, 1);
+    painter.draw_line({ scaled_size, scaled_size - 5 }, { scaled_size, scaled_size + 5 }, Color::MidGray, 1);
+    aa_painter.draw_ellipse(Gfx::IntRect(0, 0, containing_box_size, containing_box_size), Color::LightGray, 1);
+
+    return new_cursor;
+}
+
+void BrushTool::refresh_editor_cursor()
+{
+    m_cursor = build_cursor();
+    if (m_editor)
+        m_editor->update_tool_cursor();
+}
+
 }

Userland/Applications/PixelPaint/Tools/BrushTool.h

@@ -2,12 +2,14 @@
  * Copyright (c) 2020, Ben Jilks <benjyjilks@gmail.com>
  * Copyright (c) 2021, Mustafa Quraish <mustafa@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
+ * Copyright (c) 2022, Torsten Engelmann <engelTorsten@gmx.de>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once
 
+#include "../ImageEditor.h"
 #include "Tool.h"
 
 namespace PixelPaint {
@@ -21,9 +23,14 @@ public:
     virtual void on_mousemove(Layer*, MouseEvent&) override;
     virtual void on_mouseup(Layer*, MouseEvent&) override;
     virtual GUI::Widget* get_properties_widget() override;
-    virtual Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> cursor() override { return Gfx::StandardCursor::Crosshair; }
+    virtual Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> cursor() override
+    {
+        if (m_editor && m_editor->scale() != m_scale_last_created_cursor)
+            refresh_editor_cursor();
+        return m_cursor;
+    }
 
-    void set_size(int size) { m_size = size; }
+    void set_size(int size);
     int size() const { return m_size; }
 
     void set_hardness(int hardness) { m_hardness = hardness; }
@@ -41,6 +48,9 @@ protected:
     virtual Color color_for(GUI::MouseEvent const& event);
     virtual void draw_point(Gfx::Bitmap& bitmap, Gfx::Color const& color, Gfx::IntPoint const& point);
     virtual void draw_line(Gfx::Bitmap& bitmap, Gfx::Color const& color, Gfx::IntPoint const& start, Gfx::IntPoint const& end);
+    virtual NonnullRefPtr<Gfx::Bitmap> build_cursor();
+    void refresh_editor_cursor();
+    float m_scale_last_created_cursor = 0;
 
 private:
     RefPtr<GUI::Widget> m_properties_widget;
@@ -49,6 +59,7 @@ private:
     bool m_was_drawing { false };
     bool m_has_clicked { false };
     Gfx::IntPoint m_last_position;
+    NonnullRefPtr<Gfx::Bitmap> m_cursor = build_cursor();
 };
 
 }

Userland/Applications/PixelPaint/Tools/EraseTool.cpp

@@ -73,6 +73,7 @@ GUI::Widget* EraseTool::get_properties_widget()
 
         size_slider.on_change = [&](int value) {
             set_size(value);
+            size_slider.set_override_cursor(cursor());
         };
         set_primary_slider(&size_slider);
 
@@ -119,10 +120,14 @@ GUI::Widget* EraseTool::get_properties_widget()
         pencil_mode_radio.on_checked = [&](bool) {
             m_draw_mode = DrawMode::Pencil;
             hardness_slider.set_enabled(false);
+            refresh_editor_cursor();
+            size_slider.set_override_cursor(cursor());
         };
         brush_mode_radio.on_checked = [&](bool) {
             m_draw_mode = DrawMode::Brush;
             hardness_slider.set_enabled(true);
+            refresh_editor_cursor();
+            size_slider.set_override_cursor(cursor());
         };
 
         pencil_mode_radio.set_checked(true);
@@ -131,4 +136,26 @@ GUI::Widget* EraseTool::get_properties_widget()
     return m_properties_widget.ptr();
 }
 
+NonnullRefPtr<Gfx::Bitmap> EraseTool::build_cursor()
+{
+    if (m_draw_mode == DrawMode::Brush)
+        return BrushTool::build_cursor();
+
+    m_scale_last_created_cursor = m_editor ? m_editor->scale() : 1;
+    int scaled_size = size() * m_scale_last_created_cursor;
+
+    NonnullRefPtr<Gfx::Bitmap> new_cursor = Gfx::Bitmap::try_create(Gfx::BitmapFormat::BGRA8888, Gfx::IntSize(scaled_size, scaled_size)).release_value_but_fixme_should_propagate_errors();
+
+    Gfx::IntRect rect { 0, 0, scaled_size, scaled_size };
+    Gfx::Painter painter { new_cursor };
+
+    painter.draw_rect(rect, Color::LightGray);
+    painter.draw_line({ scaled_size / 2 - 5, scaled_size / 2 }, { scaled_size / 2 + 5, scaled_size / 2 }, Color::LightGray, 3);
+    painter.draw_line({ scaled_size / 2, scaled_size / 2 - 5 }, { scaled_size / 2, scaled_size / 2 + 5 }, Color::LightGray, 3);
+    painter.draw_line({ scaled_size / 2 - 5, scaled_size / 2 }, { scaled_size / 2 + 5, scaled_size / 2 }, Color::MidGray, 1);
+    painter.draw_line({ scaled_size / 2, scaled_size / 2 - 5 }, { scaled_size / 2, scaled_size / 2 + 5 }, Color::MidGray, 1);
+
+    return new_cursor;
+}
+
 }

Userland/Applications/PixelPaint/Tools/EraseTool.h

@@ -25,6 +25,7 @@ public:
 protected:
     virtual Color color_for(GUI::MouseEvent const& event) override;
     virtual void draw_point(Gfx::Bitmap& bitmap, Gfx::Color const& color, Gfx::IntPoint const& point) override;
+    virtual NonnullRefPtr<Gfx::Bitmap> build_cursor() override;
 
 private:
     virtual StringView tool_name() const override { return "Erase Tool"sv; }
@@ -35,7 +36,7 @@ private:
         Pencil,
         Brush,
     };
-    DrawMode m_draw_mode { DrawMode::Brush };
+    DrawMode m_draw_mode { DrawMode::Pencil };
     bool m_use_secondary_color { false };
 };
 

Userland/Applications/PixelPaint/Tools/PenTool.h

@@ -18,7 +18,7 @@ class PenTool final : public BrushTool {
 public:
     PenTool();
     virtual ~PenTool() override = default;
-
+    virtual Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> cursor() override { return Gfx::StandardCursor::Crosshair; }
     virtual GUI::Widget* get_properties_widget() override;
 
 protected: